The well-known prior art methods of recovering ferronickel from oxidated nickel ores comprise preparing of a charge accompanied by roasting ore, a reducing agent and flux, and followed by electric smelting of the charge. Any solid carbonaceous reducing agent, preferably the anthracite culm, can be suitably used as the reducing agent. Limestone, dolomite, or dolomitic limestone are used as the flux. The amount of the reducing agent and the flux required is determined by the ore composition. Any of such methods is an analog of the present invention.
In the above methods, the reducing agent and the flux are added to the ore prior to its processing in the roasting furnace, thus simultaneously performing the roasting of all components of the charge fed for electric smelting. In the course of roasting, a partial reduction of metal oxides and a partial binding of the free silica occur. However, adequate conditions cannot be provided for the optimal performing of both reactions in one roasting furnace. This is caused by the fact that the intensive thermal decomposition of the used flux with the isolation of the sufficient amount of lime binding free silica is provided, mainly, at temperatures above 1000.degree. C. However, at this temperature the melting of the ore components occurs, leading to the formation of skulls in the roasting furnace. On the other hand, if the roasting temperature is lower than the temperature of intensive flux decomposition, this leads to worse technical- and -economic indices of the electric smelting process. The latter manifests in an increase in the power consumption to provide the complete thermal flux decomposition and in a higher consumption of the reducing agent reacting with the carbon dioxide formed as a result of the thermal decomposition of the flux and leads to a quicker destruction of the electric roasting furnace crown and, hence, to a reduction in its utilization factor. These circumstances are especially essential in the processing of low-grade ores with a high content of silica, that require the addition of relatively large amounts of flux, ranging from 20% of the dry ore weight and over.